On Saturday, the 19-year-old jam band will become the first homegrown San Diego act to headline or co-headline for the sixth consecutive time at Chula Vista’s Sleep Train Amphitheatre.

It’s an achievement unmatched by blink-182, Jason Mraz or any other area act that has performed at the nearly 20,000-capacity venue. And it’s an achievement Slightly Stoopid co-founder Miles Doughty and his band mates don’t remotely take for granted.

“Ultimately, your fans are your boss. Because, without them, you don’t have a job,” Doughty said. “The first 10 years was a real grind for us. But it builds the character of who you are and what you can, and can’t, take. And it gives you a certain humility. We played shows (early on) where nobody was there, and we played an hour set for the bartender.

“But you don’t want to be told you can’t do it — and you have to realize this is the funnest job in the world. … We’ve been all over the world and to every state. To be able to do it this long and have as many fans as we do, you have to pinch or slap yourself, and ask: ‘Is this for real?’ When you’re playing for thousands of people on a cliff overlooking a beach in Portugal, and there’s a castle with cannons right next to you, it doesn’t get much better than that.”

Doughty and his musical colleagues experienced a similar “pinch me” moment when the band recorded its new DVD and double-CD set, “Slightly Stoopid & Friends: Live at Roberto’s TRI Studios.”

The title of their new independent release is not an homage to a certain San Diego Mexican restaurant chain the band likes to frequent. Rather, it refers to former Grateful Dead member Bob Weir’s Bay Area studio, where Slightly Stoopid recorded “Live at Roberto’s.” The 31-song collection boasts guest appearances by Weir, among others.

“The band we’ve kind of modeled ourselves after in the touring world is the Grateful Dead,” Doughty said last week from Verizon Amphitheatre in Irvine. “The Deadheads are the most loyal fans there are. And we have our Stoopidheads, who have kept (our) band going for so long. …

“(Weir) had heard of us, because we do a lot of the same festivals around the country. What was cool is he really embraced us and gave us a chance to use his TRI Studios. The best thing was when I was in his dressing room and we were practicing (vocal) harmonies on (the Dead classic) ‘I Know You Rider.’ I was like: ‘Holy crap — I’m sitting here singing with Bob Weir!’ ”